smoke is not good for your lungs, tobbacco companies add stuff to tobbacco, thus making it less good for your lungs, weed smoking is not good for your lungs, is it equal to 20 cigarettes, no, is it equal to 1, i dont know, but all smoke=bad for lungs, its just the degree to which you will sacrafice yourself for something you like, its a decision i wasnt willing to make until recently, and i dont have a problem with it, i think the amount that i smoke will overall not affect my life in a way that something else couldnt, ever since ive started smoking ive lost 50 lbs due to dieting, and i would rather inhale smoke than be dangerously overweight. The feeling of my lungs after a heavy smoke session will pass in a day, but 50 lbs is something i have to carry with me, but that is my take on smoking.